1. Field of the Invention
The present invention relates to a system for recognizing a face, and more particularly, to an apparatus and method for accurately detecting eyes from an input face image.
2. Description of Related Art
Face recognition systems identify one or more humans' faces in a still or moving picture using a face database. Such a face recognition system extracts only a face region to be recognized from an input face image using a scanner in a case of a still picture or using a charge coupled device (CCD) camera installed for security in a bank or a personal computer (PC) camera mainly used in Internet visual chatting in a case of a moving picture and extracts the major characteristics of the face region. For example, the face recognition system extracts the characteristics such as eyes, nose, mouth, counter of a face and compares the extracted characteristics with the characteristics stored in a face database to recognize the face.
A process of detecting face components or accurate positions of the characteristics of a face from an extracted face candidate region is required in order to input an extracted face candidate image to the face recognition system. In other words, in order to compare an input image with a model, position extraction and size normalized processes for compensating differences in size, rotation direction, and position between a face image extracted from the input image and a face image of a model template are required as essential previously-completed processes for improving recognition and matching performances. Most face recognition systems use eye regions or the central regions of the pupils as face elements for arrangement and normalization processes. This is because the characteristics of the eye regions of the face elements do not change even though the size, expression, and posture of the face image and illumination vary. Thus, it is very important to exactly detect the positions of eyes.
U.S. Pat. No. 5,293,427, entitled “Eye position detecting system and method therefore,” discloses a technique for detecting eye position by a difference between an infrared image and a binarized general image using an infrared strobe. However, in this technique, the infrared strobe is required, and when a face is presented for detection wearing eyeglasses, afterimages are formed on the lenses of eyeglass.
Also, in a conventional eye detecting method, eyes are detected by performing a morphology operation, a histogram analysis, or the like with respect to the entire face image. Thus, the conventional eye detecting method is sensitive to a variation of illumination. Moreover, both eyes cannot be accurately detected at the same time.